Conventional fuel systems include a pump, one or more fuel injectors, and a distribution network for directing the pressurized fuel from the pump to the fuel injectors. Over time, the different components of the fuel system wear, causing efficiency losses and/or gradual deviations from desired operating pressures. If these losses and pressure deviations are left unchecked, the performance of the engine may deteriorate. In addition, if the wear is excessive or damage to a component of the system occurs, extreme system pressure drop and/or collateral damage may be possible, leaving the engine inoperable. When the engine becomes inoperable at a time that a host machine is away from a service area, repairs to the system may become time consuming, difficult, and costly. However, if the efficiency losses and pressure deviations can be monitored, corrective and/or precautionary actions may be timely implemented.
One example of a monitoring system is described in U.S. Patent Publication No. 2013/0013174 (the '174 publication) of Nistler et al. that published on Jan. 10, 2013. Specifically, the '174 publication discloses a method for monitoring operation an engine fuel system. The method includes stopping fuel injection during an engine coast-down event, closing an inlet metering valve of a pump, and monitoring a subsequent pressure decay rate of an associated common rail. When the pressure decay rate is greater than a decay threshold after a designated duration, the system presents a visual or audio indication of the condition to an operator.
Although the system of the '174 publication may be helpful in detecting some fuel system efficiency loss and/or pressure deviation, the system may provide limited benefit. In particular, some failure modes (e.g., when a pump outlet valve fails) can actually result in a lower-than normal pressure decay rate during a coast-down event. This type of failure mode may not be detectable via the system of the '174 publication. In addition, it may be helpful to know more information about a system inefficiency and/or pressure deviation beyond merely its existence.
The system of the present disclosure solves one or more of the problems set forth above and/or other problems of the prior art.